A pocket door is a type of door most commonly used in residential construction which opens by sliding along a track into a pocket enclosed within a wall. The door may likewise be closed by sliding it out of the wall pocket and across a doorway opening. When in the open position, the pocket door is hidden within the wall pocket and as such makes a more efficient use of available space than conventional hinged doors which swing into and take up space within rooms they are opened into.
A door opening for receiving a pocket door is ordinarily bounded by a frame header above and on either side by what are known as trimmers to those skilled in the art. Pocket door mounting systems commonly embody a track fastened directly to the frame header of the door opening. This track extends along the top of the door opening and into the wall pocket. One or more roller assemblies, from which hang the pocket door, ride along this track. In operation, the door suspended from the roller assembly is free to move in and out of the pocket in order to close and open the door.
When the door is fully open and residing within the wall pocket, the edge of the door should be flush with a jamb on the side of the door opening nearest to the wall pocket. The door should be flush with the jamb for the door's full height, top to bottom. Likewise, when the door is suspended from the track in the closed position, the edge of the door should fit neatly against the opposite trimmer or door jamb, top to bottom. Thus, necessary for a neat installation of the pocket door are these two conditions of having the edge of the door flush with the door trim when the door is open and having the edge of the door neatly fit against the jamb when the door is closed. In addition, if the pocket door is out of square with the door opening, it may have the additional problem of not being able to smoothly move along the track, or it might fail to clear the floor as it opens or closes.
As frequently occurs with the installation of job-hung pocket doors, it may not be possible to ensure the pocket door will remain completely square in the door opening as time passes. A particular difficulty arises with mechanical changes in the timber of the frame itself. The frame header in particular has been known to shrink as it dries bringing the pocket door out of square with the door opening.
Pocket doors are difficult to install in a manner which does not lead to the problems discussed above. The difficulty is compounded by the fact that a framing crew usually installs the pocket door mounting system and a separate finish crew installs the door itself. Heretofore, to correct a misalignment of the pocket door it has been necessary in practice to remove and reinstall the door jamb and trim in a complex and difficult operation.